In the manufacturing process of a semiconductor device, it is necessary to inspect the shape or its arrangement of the bonding pad of a chip main surface, a ball, etc. The inspection method of the shape of a ball and the device used for it are indicated by Japanese Unexamined Patent Publication No. Hei 5-160230 (Reference 1). In 0024-0025 paragraphs of this Reference 1, the method of making reflected light from the wire not being a photography object a faded image, and projecting brightly only the ball being an object for photography by further opening the diaphragm of an optical system wide and making shallow depth of focus (depth of field) after lessening incidence to the objective lens of the reflected light from a semiconductor chip main surface as much as possible by using the illumination from low irradiation angles with a low irradiation-angles ring shape illuminator, is indicated.
[Patent Reference 1] Japanese Unexamined Patent Publication No. Hei 5-160230